Multiple-exposure attachment for cameras.



H.. G. vDIGWEED. MULTIPLE EXPOSURE ATTACHMENT FOB CAMERAS.

APPLICATION FILED MAY 31, 1913. 1,068,862. Patented July 29, 1913.

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RICHARD GEORGE mswsnn, .trvnnroor.,v mineralen, assreno'onoiin- .l ki

JOHN PERCY JONES, or. .1.ivnn1ooLnNeLn;q-n

MULTrrLnr-Exr'osiinn Mittermeier',

Spezt-fication of Letters Ifatentl I appucationnia nay e1, ima. H'ferial 1w. 771,045.

' have invented a certain new and useful Multiple-Exposure lAttachment for Cameras, of which the following is a specification.

The invention relates more particularlyto multiple exposure attachments which are connected to the mount for the lens so that said attachment may be rotated for producing a composite negative, wherein dlfferent sections of the composite picture are produced by successive exposures.

An object of the invention is to provide an attachment of the above character, in which the opening is so constructed that a uniform diffusion of the two pictures on the one plate at the point of meeting is secured.

In the accompanying drawings z-Figure 1 is a sectional plan view of a camera lens mount with my invention applied thereto; Fig. 2, a rear view of the lens cap separate from the lens mount; F ig. 3 is a perspective view of the lens cap; and Fig. 4 is a view showing the first and second exposures, and illust-rates how one exposure merges into the other without any sharp line of demarcation across the middle of the photograph.

According to the preferred method of carrying this invention into practice, a lens cap A is taken, which in the drawing consists of a disk bounded by a lateral flange. A section is cut out of this disk or front portion of the cap, so as to leave an opening B, whose arc shaped boundary line b passes through the optical axis of the lens. The curvature of the boundary line is the same as that of the boundary of the lens, so that approximately about a third part of the front face of the cap is cut away, leaving the un-cut part in the form of a thick crescent. A mark C is made upon the cylindrical surface of the cap immediately vertically above the center of the cap when the cut out portion D lies in a vertical position. The cap A itself is made as an ordinary lens cap, but with the part B cut out. It should fit accurately the lens mount D and is made of some nonactinic substance preferably painted dead black .with at velvet lining E inside.

In use the device is employed as follows The cap A lis placed over the front of the lens mount D with the mark C on its cylindrical surface exactly above theV center of the lens and opposite the mark H on the lens mount. If an `ordinary lens cap is to be employed this is placed over the device A. The sitter is posed in one of the two positions shown in Fig. 4, and an exposure made either by the ordinary lens cap or by the shutter, then the lens cap is replaced, and the sitter re-posed so as to occupy the other of the two positions shown in Fig.- 4. The device A is turned around so that another center mark at C comes opposite the center mark H on the lens mount, and the sitter in the two positions appears upon a' single plate with no boundary line between 4them and. admits of taking the identical sitter, not reflections, in any`position and in any light. The opening B fully exposes one part of the plate at the first exposure, and graduates the exposure of the other part, and when the cap A is turned around, its opening fully exposes the unexposed part, and graduates the already exposed'part. A good sharp photograph is thus produced, and the arc shaped boundary line in conjunction with the convexity of the front face of the lens, acts to produce a uniform diffusion of the two pictures on one plate, at the place of meeting.

Of course the device may be made in any suitable form of diaphragm either in the form of a lens cap or a slide, and either in front or behind the lens. The term cap is therefore used hereinafter as defining broadly a slide, diaphragm, or other form of shutter. The above described curve b is found to give the best results.

I declare that what I claim is A multiple exposure attachment for cameras, comprising a cap adapted to be rotatably fsupported on the mount for the In witness whereof, I have hereunto 10 lens, said cap having a section cut out vfrom lsigned my name this 21st day of May, 1913, its front face forming an opening havlng an in the presence of two subscribing Witnesses.

'arc-shaped boundary line passing through the optical -axisfof the lens, said arc-shaped RICHARD GEORGE DIGWEED. boundary line acting in conjunction with the convexity of the front surface of the lens to Witnesses:

produce a uniform diiusion of the pictures G. C. DYMoND, on the plate at the place of meeting. G. H /HoYLn 

